German Patent Disclosure Document 30 11 643 and corresponding U.S. Pat. No. 4,409,086, HAAS et al., disclose an electrolysis apparatus with cell chambers through which the electrolyte flows. Anodes in the form of plate packets are disposed in these chambers via current-carrying center pins, each between two cathode plate packets; the electrode plates, which are offset from one another, each protrude into the plate gaps of opposite polarity, and the center pins comprise a core of highly conductive copper with a jacket coating of titanium. The center pins have contact straps on their outer jacket that serve to secure the anode plates and comprise platinum-plated titanium. The copper core of the center pins is provided with a bore, into which a screw body provided for establishing electrical contact is introduced.
Another similar arrangement is known from U.S. Pat. No. 3,940,328, THOMAS et al., in which a tubular valve metal body surrounds a hollow-cylindrical copper core; by spot welding, the outer face of the jacket-like valve metal body is provided with connecting elements of expanded metal that are joined to the flat, dimensionally stable active electrode parts.
In these known arrangements, the bond between the copper and titanium may weaken over the course of time, either from the invasion of air with attendant heating, from heating caused by an overflow or heating upon reactivation of anodes, or from aging; the result is an increase in the voltage drop. Previously, if predetermined threshold values for the voltage drop were exceeded, then the relatively expensive removal of the power lead from the active parts of the electrode was necessary.